Sometimes the pulp3 migration rake task fails with errors around katello_events and candlepin_events:

<pre>
Prepare content for Pulp 3:
{:services=>
  {:candlepin=>{:status=>"ok", :duration_ms=>"377"},
   :candlepin_auth=>{:status=>"ok", :duration_ms=>"57"},
   :foreman_tasks=>{:status=>"ok", :duration_ms=>"4"},
   :katello_events=>
    {:status=>"ok", :message=>"0 Processed, 0 Failed", :duration_ms=>"0"},
   :candlepin_events=>
    {:status=>"FAIL", :message=>"Not running", :duration_ms=>"1"},
   :pulp3=>{:status=>"ok", :duration_ms=>"402"},
   :pulp=>{:status=>"ok", :duration_ms=>"245"},
   :pulp_auth=>{:status=>"ok", :duration_ms=>"139"}},
 :status=>"FAIL"}
rake aborted!
Not all the services have been started. Check the status report above and try again.
</pre>